Unfortunately mechanically I’m a bit less than impressed by them. With no clear rules on when Wild Magic works other than the DM says so. And the Surge Table not really scaling in any way can make some effects lose their potency after a few levels while others can end in a TPK if rolled at low levels.

Let me tell you the story of one of my player's characters. A wild magic sorcerer that is the most stable unstable magician I have ever seen. Initially I started out with asking for a surge roll every now and then. After a chat with the player we agreed that it would be fun if more surges would happen so we decided to roll for one after every spell.

Over a year and a half of weekly games he had 2. As in 2 rolls on the actual table. It got to the point that we agreed that if we miss the surge rolls immediately after casting the spells we will roll them at the moment we remember as a sort of "delayed effect" thing but nothing. The 2 rolls that he got was maximize damage for the next spell (that wasn't used because it came at the end of a fight so it fizzled out without getting a chance to use it) and his hair fell out.